Great for a group and; you can make ahead and bake later
1/4 c. unsalted butter
1-1/2 t. Dijon mustard
1-1/2 t. honey
1/2 t. garlic powder
salt and black pepper
12 pretzel buns, sliced (dinner roll size)
1-1/2 c. fresh baby spinach
1 pound deli-style roast beef
8 oz. brie cheese, sliced thin (see Note below)
3 Tbls. unsalted butter
2 large yellow onions, sliced thin
1/2 t. salt
2 Tbls. brown sugar
Begin by preparing your caramelized onions. Melt 3 tablespoons of butter, in a large skillet, over low heat. Add the onion- and salt. Cook on low, stirring occasionally, until the onions soften and begin to caramelize, about 20-25 minutes. Sprinkle on the brown sugar and stir to combine. Cook for an additional 5-10 minutes. Remove from heat and set aside.
Preheat your oven to 350 degrees F.
Butter Sauce: In a small saucepan, melt the unsalted butter over medium-low heat. Whisk in the mustard, honey, garlic powder and a dash of salt and black pepper. Cook for 1-2 minutes more and then remove from heat.
In a 9x13-inch baking dish or foil pan, brush two tablespoons of the melted butter on the bottom of the dish.
Take the bottoms of your rolls and place them in the baking dish. Layer on baby spinach (I like several leaves), roast beef and a thin slice of brie or other type of cheese. Top with caramelized onions (be generous). Place the tops of the rolls on top. Brush the remaining melted butter mixture directly on top of the rolls.
Cover the dish with foil and bake for 15-20 minutes or until the cheese has melted.
Remove from heat and serve immediately. Enjoy!